代理模式(大话设计模式)C/C++版本

代理模式

C++

#include <iostream> using namespace std;  class Subject // Subject 定义了RealSubject和Proxy的共用接口..这样就在任何使用RealSubject的地方都可以使用Proxy { public:     virtual void func()     {         cout << "Subject" << endl;     } };  class RealSubject : public Subject // RealSubject  定义proxy所代表的真实实体 { public:     virtual void func()     {         cout << "RealSubject" << endl;     } };  class Proxy : public Subject // proxy 保存一个引用使得代理可以访问实体,并且提供一个于Subject的接口相同的接口 这样代理就可以用来替代实体 {     RealSubject real;  public:     virtual void func()     {         cout << "Proxy" << endl;         real.func();     } };  int main() {     Proxy proxy;     proxy.func();     return 0; } 

C

#include <stdio.h>  typedef void (*FuncPtr)(void);  typedef struct {     FuncPtr func; } Subject;  typedef struct {     Subject subject; } RealSubject;  void RealSubject_init(RealSubject *self); void RealSubject_func(void);  typedef struct {     Subject subject;     RealSubject real; } Proxy;  void Proxy_init(Proxy *self); void Proxy_func(Proxy *self);  int main() {     Proxy proxy;     Proxy_init(&proxy);     proxy.subject.func();     return 0; }  void RealSubject_init(RealSubject *self) {     self->subject.func = RealSubject_func; }  void RealSubject_func(void) {     printf("RealSubject\n"); }  void Proxy_init(Proxy *self) {     RealSubject_init(&self->real);     self->subject.func = (FuncPtr)Proxy_func; }  void Proxy_func(Proxy *self) {     printf("Proxy\n");     self->real.subject.func(); }